DiskBroom › What it cleans › What "System Data" on Mac actually is
Settings → General → Storage (not one location)
System Data is macOS's catch-all label for everything its storage chart can't classify: app caches, logs, temporary files, Time Machine local snapshots, virtual-machine files, browser profiles, old iOS backups, and more. There is no single folder to delete — the number is a sum of many places.
Commonly 10–50 GB; 100 GB+ appears regularly on machines with local snapshots, developer tools, or virtualization. The number in Settings often runs ahead of what any tool can itemize.
It depends entirely on which slice you touch — which is why blanket "clear System Data!" advice is a red flag. Caches and logs regenerate. Local snapshots thin automatically as disk fills, or can be removed by hand. Old device backups and VM disks are yours to judge.
Worth a look. Mixed contents: some slices regenerate harmlessly, others (backups, VM disks) are unique data. Look before anything goes.
Honest scope note: DiskBroom surfaces the cache, log, and temp portion of System Data that lives in your home folder — the part that's safe to itemize. Local snapshots, VM disks, and device backups are outside its catalog, and this page tells you how to handle those yourself because a storage tool that pretends to cover everything is lying to you.
Prefer not to do this by hand every time? DiskBroom scans this location (and every other one on its published list), shows the size, rates the risk with the same shape you see above, and asks before anything moves — everything goes to the Trash, never past it. Scanning is free forever.
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